Vertex Dynamics Simulations of Subgrain Growth in Al-0.1%mn Binary Alloys : Effect of Crystallographic Orientation

The present study aims to investigate the effect of crystallographic orientation on thekinetics of recovery in deformed samples of the Al-0.1%Mn binary alloy using vertexdynamics simulations of subgrain growth.In order to characterize the recovery kinetics experimentally, a polycrystalline bar ofthe alloy was cold rolled to a true strain of 3.96. Samples extracted from the rolled bar weresubjected to isothermal annealing at four temperatures for different durations. Microhardnessmeasurements were made on each sample and the activation energy for recovery wasestimated using these measurements and the recovery kinetics model developed byVandermeer and Hansen. Several practical difficulties were encountered when using thismodel, most notably due to the complexity of the model equations and the amplification ofexperimental uncertainty by exponential functions in the model. The activation energy foundwas therefore not reliable.Using the material properties mentioned in the literature, vertex dynamics simulationsof subgrain growth were carried out. Deformation microstructures of monocrystals havingBrass and Goss orientations were reproduced in the simulations. Good agreement with theexperimental results of of Albou et al. was achieved. The low rate of recovery in Brasscrystals was due to the presence of subgrain boundaries of low disorientations. The Gossdeformation microstructure consists of bands with subgrain boundaries of highdisorientations which lead to high mobilities boundaries and this led to subgrain growth in theGoss crystal. Thus the effect of crystallographic orientation is related to the deformationmicrostructure, the subgrain boundaries and the distribution of their disorientations.tel-00862402,version1-16Sep2013